ML031611051
| ML031611051 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 06/10/2003 |
| From: | Bateman W Division of Engineering |
| To: | Terry C Nine Mile Point |
| References | |
| Download: ML031611051 (5) | |
Text
June 10, 2003 Carl Terry, BWRVIP Chairman Constellation Generation Group Nine Mile Point Nuclear Station Post Office Box 63 Lycoming, NY 13093
SUBJECT:
BWR TOP GUIDE INSPECTION AND FLAW EVALUATION GUIDELINES FOR LICENSE RENEWAL
Dear Mr. Terry:
By letter dated December 7, 2000, the staff found the BWRVIP-26, BWR Top Guide Inspection and Flaw Evaluation Guidelines, report to be acceptable to reference in a license renewal (LR) application to the extent specified and under the limitations delineated in the LR safety evaluation report (SER) dated September 29, 1999. Renewal applicant Action Item 4.1(4) indicates that due to the susceptibility of the top guide beams to irradiated assisted stress corrosion cracking (IASCC), applicants referencing the BWRVIP-26 report for license renewal should identify and evaluate the projected accumulated neutron fluence as a potential time-limited aging analysis (TLAA) issue.
Exelon Generation Company, in its application for license renewal for the Peach Bottom Atomic Power Station, Units 2 and 3 (
Reference:
Letter from Exelon dated July 2, 2001), identified that IASCC of the top guide requires a TLAA. The staff review of this evaluation is contained in the letter dated February 5, 2003, from P. T. Kuo (NRC) to M. P. Gallagher (Exelon Corporation),
License Renewal Safety Evaluation Report for Peach Bottom Atomic Power Station, Units 2 and 3.
In the BWRVIP-26 report, the BWRVIP lists 5 x 1020 n/cm2 as the threshold fluence beyond which components may be susceptible to IASCC. The location on the top guide that will see this high fluence is the grid beams. This is location 1, as identified in BWRVIP-26, Table 3-2, Matrix of Inspection Options. In its evaluation of the top guide assembly, including the grid beam, General Electric (GE) assumed a lower allowable stress value, acknowledging the high fluence value at this location. The conclusion of this analysis, and the fact that a single failure at this location has no safety consequence, was that no inspection was considered necessary to manage this potential aging effect.
The staff is concerned that multiple failures of the top guide beams are possible when the threshold fluence for IASCC is exceeded. According to BWRVIP-26, multiple cracks have been observed in top guide beams at Oyster Creek. In addition, baffle-former bolts on PWRs that exceeded the threshold fluence have had multiple failures. In order to exclude the top guide beam from inspection when its fluence exceeds the threshold value, an analysis must be provided to demonstrate that failures of multiple beams (all beams that exceed the threshold
Carl Terry fluence) will not impact the safe shutdown of the reactor during normal, upset, emergency, and faulted conditions. If this cannot be demonstrated, then an inspection program to manage this aging effect to preclude loss of component intended function is required.
In Attachment 3 to a letter from M. P. Gallagher to USNRC dated January 14, 2003, Exelon provided a revised Reactor Pressure Vessel and Internals ISI Program which indicates Peach Bottom will perform augmented inspections for the top guide similar to the inspections of control rod drive housing (CRDH) guide tubes.
The staff believes that a comprehensive evaluation of the impact of IASCC and multiple failures of the top guide beams is necessary, and that an inspection program for top guide beams for all BWRs should be developed by the BWRVIP to ensure that all BWRs can meet the requirements of 10 CFR Part 54 throughout the period of extended operation. Therefore, the staff requests that the BWRVIP undertake this evaluation and provide the staff with its results and conclusions. Please note that this issue has been discussed with Robin Dyle, Technical Chairman BWRVIP Assessment Committee. Please contact Barry Elliot of my staff at 301-415-2709 if you have any further questions regarding this subject.
Sincerely,
/RA/
William H. Bateman, Chief Materials and Chemical Engineering Branch Division of Engineering Office of Nuclear Reactor Regulation cc: BWRVIP Service List
Carl Terry fluence) will not impact the safe shutdown of the reactor during normal, upset, emergency, and faulted conditions. If this cannot be demonstrated, then an inspection program to manage this aging effect to preclude loss of component intended function is required.
In Attachment 3 to a letter from M. P. Gallagher to USNRC dated January 14, 2003, Exelon provided a revised Reactor Pressure Vessel and Internals ISI Program which indicates Peach Bottom will perform augmented inspections for the top guide similar to the inspections of control rod drive housing (CRDH) guide tubes.
The staff believes that a comprehensive evaluation of the impact of IASCC and multiple failures of the top guide beams is necessary, and that an inspection program for top guide beams for all BWRs should be developed by the BWRVIP to ensure that all BWRs can meet the requirements of 10 CFR Part 54 throughout the period of extended operation. Therefore, the staff requests that the BWRVIP undertake this evaluation and provide the staff with its results and conclusions. Please note that this issue has been discussed with Robin Dyle, Technical Chairman BWRVIP Assessment Committee. Please contact Barry Elliot of my staff at 301-415-2709 if you have any further questions regarding this subject.
Sincerely,
/RA/
William H. Bateman, Chief Materials and Chemical Engineering Branch Division of Engineering Office of Nuclear Reactor Regulation cc: BWRVIP Service List Distribution:
EMCB R/F ACRS Mweston GMHolahan MEMayfield NCChokshi CE Moyer WCullen Accession No.: ML031611051 INDICATE IN BOX: C=COPY W/O ATTACHMENT/ENCLOSURE, E=COPY W/ATT/ENCL, N=NO COPY OFFICE EMCB:DE EMCB:DE DRIP:RLEP EMCB:DE NAME MKhanna/BElliot SCoffin PTKuo WHBateman DATE 05/ 28 /03 5 / 30 /03 6 / 20 / 03 6 / 3 /03 OFFICIAL RECORD COPY
Carl Terry cc:
terryc@nimo.com vaughn.wagoner@cplc.com rldyle@southernco.com johna.wilson@exeloncorp.com Gary.Park@nmcco.com richard.ciemiewicz@exeloncorp.com bcarter@epri.com ldsteine@epri.com kwolfe@epri.com rpathani@epri.com tmulford@epri.com Bill Eaton, BWRVIP Vice Chairman General Manager, Plant Operations Entergy Operations, Inc.
Grand Gulf Nuclear Station PO BOX 756, Waterloo Rd Port Gibson, MS 39150-0756 Robin Dyle, Technical Chairman BWRVIP Assessment Committee Southern Nuclear Operating Co.
40 Inverness Center Parkway Birmingham, AL 35242 H. Lewis Sumner, Executive Chair BWRVIP Mitigation Committee Vice President, Hatch Project Southern Nuclear Operating Co.
M/S BIN B051, PO BOX 1295 40 Inverness Center Parkway Birmingham, AL 35242-4809 Richard Ciemiewicz, Technical Vice Chair BWRVIP Assessment Committee Exelon Corp.
Peach Bottom Atomic Power Station M/S SMB3-6 1848 Lay Road Delta, PA 17314-9032 Michael McMahan, Executive Chair BWRVIP Assessment Committee Vice President, Project and Outage Mgmnt.
Exelon Corporation Cornerstone II at Cantera 4300 Winfield Rd.
Warrenville, IL 60555-4012 Gary Park, Technical Chairman BWRVIP Inspection Focus Group Nuclear Management Co.
DAEC Plant Support Center 3313 DAEC Road Palo, IA 52324-9646 Vaughn Wagoner, Technical Chair BWRVIP Integration Committee Progress Energy One Hannover Square 9C1 P.O. Box 1551 Raleigh, NC 27612 John Wilson, Technical Chair BWRVIP Mitigation Committee Nuclear Chemistry Manager Exelon Corporation Cornerstone II at Cantera 4300 Winfield Rd.
Warrenville, IL 60555-4012
Carl Terry Al Wrape, Executive Chair BWRVIP Integration Committee General Manager, Nuclear Engrg.
PPL Susquehanna, LLC 2 N 9th Street Allentown, PA 18101-1139 Denver Atwood, Technical Chair BWRVIP Repair Focus Group Southern Nuclear Operating Co.
Post Office Box 1295 40 Inverness Center Parkway Birmingham, AL 35201 Robert Carter, EPRI BWRVIP Assessment Manager Greg Selby, EPRI BWRVIP Inspection Manager EPRI NDE Center P. O. Box 217097 1300 W. T. Harris Blvd.
Charlotte, NC 28221 Tom Mulford, EPRI BWRVIP Integration Manager Raj Pathania, EPRI BWRVIP Mitigation Manager Ken Wolfe, EPRI BWRVIP Repair Manager Larry Steinert, EPRI BWRVIP Electric Power Research Institute P. O. Box 10412 3412 Hillview Ave.
Palo Alto, CA 94303